Abstract: He--Ne gas discharge tube having a cylindrical tube body with an inside cathode cylinder and end walls which are inserted into ends of the tube body and which have for two capillary tubes, outside ends of which are closed by means of Brewster windows, exhaust pipe and connecting pin for the cathode cylinder. The tube, the end walls and the capillary tubes consist of calcium alkalisilicate glass or calcium alumosilicate glass. The end walls are sealingly connected by means of glass solder to the tube body, the capillary tubes, the exhaust pipe and the cathode connecting pin. The He--Ne gas discharge tube is characterized by a high helium tightness.

Abstract: A ring laser for a ring laser type of gyro having a block with an optical resonator cavity therein and three corner mirrors and an amplifier element for optical frequencies. The amplifier element is adjustable and alignable with respect to the block in such a way that it is adaptable mechanically to the beam path resulting from the mirror arrangement determined by the production technology. The production depends basically on arranging the mirrors in such a way that a resonant beam path results. As tolerances with regard to the accuracy of the position of the amplifier element are considerably lower than those with regard to the positions of the mirrors, the position of the amplifier element is specified.

Abstract: A ring laser particularly for a ring laser type of gyro in which the ring ser includes three corner mirrors and a separate gas discharge tube arranged in a recess in a block. The gas discharge tube is mounted on the block longitudinally of the beam path by at least one piezo electric drive. The modulation amplitude of the separated beam portion is measured by a control circuit and is converted into a high voltage adjustment signal for the drive as a function of the modulation amplitude. Two drives may be spaced apart in the longitudinal direction of the gas discharge tube and these can be controlled independently of each other. Although the beam path may be displaced as a result of thermal expansion and/or bending of the block, the gas discharge tube may be kept exactly coaxial with the beam which traverses it.

Abstract: The rotational vibration drive consists of a first plate attachable to a ed baseplate and a second plate attachable to a clamping plate for the ring laser block. The first and second plates are arranged side by side in the same plane. A torsionally stiff rotational spring linkage joins the first and second plates and has a rotational axis perpendicular to the plane of the beam path of the ring laser. The first and the second plates together with the rotational spring linkage are of unitary construction. Two slots originating from the rotational spring linkage extend between the first and the second plates. A piezoceramic stack drive is arranged in mutually-aligned holes in the first and second plates and acts between the said first and second plates, the axis of the piezoceramic stack drive being positioned centrally in height between surfaces of the first and second plates.

Abstract: A piezoceramic servo-drive for producing translational and angular moveme especially for application to ring laser mirrors, and including piezo discs arranged in a column. The discs are polarised in such a way that the direction of extension of the column and the direction of the electrical field lie in parallel. The discs are provided on one side with a complete contact surface and on the other side are divided into electrically separate contact segments which are provided with separate electrical connections.

Abstract: A ring laser, especially for a ring laser type of gyro, comprising a block roduced from a thermally and mechanically highly-stable ceramic glass and three corner mirrors. At least one of the mirrors can be tilted about an axis by a servo-drive and one of the mirrors is a semi-transparent separating mirror, behind which is arranged a photo-detector in the beam path of the separated beam portion of one of the rotating wave trains. The photo-detector may at least be one photo-diode which is arranged in such a way that it gives an output signal proportional to the position of the beam, as a function of which an adjustment signal is formed for the servo-drive of the tiltable mirror. Two photo-diodes can be provided alongside or on top of each other in the plane of the beam. The photo-diodes are in the form of a differential photo-diode. In order to eliminate errors, one of the corner mirrors is tiltable about an axis perpendicular to the plane of the beam path.

Abstract: A ring laser having at least three corner mirrors, of which one carries a ferromagnetic garnet layer on a substrate and is coated with a plurality of interference layers and magnetized at right angles to the ferromagnetic garnet layer. The ring laser is designed in such a way that the corner mirror which carries the ferromagnetic garnet layer acts in reflection as a Faraday cell and, in particular, in that the ferromagnetic garnet layer is subjected to circularly polarized radiation. The circularly polarized radiation may be produced by arranging in front of the corner mirror which carries the ferromagnetic garnet layer a .lambda./4 retarding plate. Another possibility consists in providing those corner mirrors which in the radiation path are adjacent to the corner mirror which carries the ferromagnetic garnet layer with a plurality of interference layers which are arranged in such a way that circularly polarized radiation is converted into linearly polarized radiation by means of a 90.degree.